This is a very nice plugin - excellent in fact!
One small thing: the visual difference between the icon states seem reversed to me. That is, the state for a "good" site is more noticeable (and appears more urgent) than the "bad" site one.
This seems to be due to the use of more red in the good state, and a slightly confusing icon which shows a network diagram (indicating something to do with a network of course). So I have to think twice each time I see the icon - and the use of the strong red colour draws my eye to it unnecessarily.
Perhaps the "good" state should not have a graphical icon at all and just a request count, while the bad one should have the red network diagram?
Other than that tiny niggle - it's perfect.